Batteries are essential elements of many electronic devices, systems, and networks. Banks of batteries often supply backup power for telephone networks and computer networks including and not limited to clusters of computer servers for web hosting and cloud computing. Banks of batteries also are found in solar power and wind power networks. In those networks, the battery banks store energy during times of peak production to supply electrical power when the sun is not shining or the wind is calm. As data centers proliferate and as solar and wind power grow, it is important to monitor batteries that backup servers and store energy.
Batteries are an important component to the uninterruptable power supply (UPS) for a network of computers or computer servers. The UPS has a mains power input that is converted to direct current by a rectifier in order to charge the batteries in the bank. At the UPS output, an inverter converts the direct current into alternating current to supply power to the network.
Each battery in the bank is an electrochemical apparatus with a finite life. Individual batteries require inspection, maintenance, repair, and replacement. Typical measurements include temperature, voltage, current, internal resistance, impedance, conductance, battery condition, and the date and time of the measurements. Temperature extremes, alternating ripple voltage and current reduce battery life. Batteries may be kept in rooms with controlled temperatures, but it is important to monitor the amount of AC ripple on a battery. As batteries age, their internal resistance increases and that also reduces their life. Other measured parameters include DC and AC voltage and current.
Batteries in a bank are typically numbered sequentially. A first battery in a string, array, or matrix of batteries may be labeled number “1” and subsequent batteries increase the number by one for each battery. A battery tester has internal memory. The battery tester's memory holds both the test results and the label that identifies each battery.
As the technician or engineer uses the battery tester to sequentially test each battery, the tester successively increments the value of the label and records both the label and the test results for each battery in memory. The battery tester increments the value of the label for each successive battery so that the label correlates the test results (and time-stamp) with the label of each battery. For example, after battery number “1” is tested and its results are stored in memory with the label “1,” the tester increments the label to labeled memory location “2” and is ready to store the tests results for battery number “2.”
During a typical test, a first technician holds an instrument, such as a multimeter or battery tester, that performs and records test measurements. The battery tester has a pair of conductors extending from its body and terminates in a pair of probes. A second technician manipulates the probes to contact terminals of the battery. Since a battery may be installed in a position that makes probing difficult, extender arms may be attached to the probes to enable the technician to reach the battery.
When testing a large number of batteries, it is difficult to correctly associate the stored test results to the battery that generates the results. Since there may be hundreds of batteries and hundreds of test readings, the correct test reading must be correlated to the correct battery. Because testing is repetitious and fatiguing, mis-probing is common and often there are more readings recorded than there are actual batteries, indicating that one or more batteries have been tested twice. When such errors occur, it is time consuming to find a specific battery that may have failed a test or is beginning to show signs of failure.
One approach to making sure stored readings correlate to the correct battery is to show the number of the battery under test on the display of the battery tester. However, viewing the display is often very difficult as the technician must pay strict attention to the position of the test probes in the high-energy environment of the battery bank. To mitigate this problem, often a second technician follows the first technician to keep track of the numbering and to hold the battery tester. This allows the first technician to devote his or her full attention to correctly placing the probes on the battery terminals. Nevertheless, even when two technicians conduct the testing, mistakes in matching the test results with the batteries in the bank are still common.